Adjustable drain for spark erosion machine



Aug. 16, 1966 G. KINTZ EL ETAL ADJUSTABLE DRAIN FOR SPARK EROSION MACHINE 5 Sheets-Sheet l Filed Dec.

Aug. 16, 1966 G. KINTZEL ETAL ADJUSTABLE DRAIN FOR SPARK EROSION MACHINE 5 Sheets-Sheet 2 Filed Dec. 2, 1963 M18. 16, 1966 a. KINTZEL ET'AL 3,266,519

ADJUSTABLE'DRAIN FOR SPARK EROSION MACHINE Filed Dec. 2, 1963 5 Sheets-Sheet :5

United States Patent 3,266,519 ADJUSTABLE DRAIN FOR SPARK EROSION MACHINE Gerhard Kintzel and Gerhard Nitsche, Langen, near Frankfurt am Main, Germany, assignors to Nassovia Werkzeugmaschinenfabrik G.m.b.H., Langen, near Frankfurt am Main, Germany Filed Dec. 2, 1963, Ser. No. 327,237 Claims priority, applicatig; Ge7rmany, Dec. 22, 1962,

2 9 3 Claims. (Cl. 137-579) This invention relates to an adjustable drain tube for draining liquid from the workpiece holding tank of a spark erosion machine.

The spark erosion of a workpiece is usually done in a tank holding the workpiece which is covered by a dielectric liquid such as petroleum. Inasmuch as this liquid becomes very dirty from the particles composed of residual metallic oxides and from the spark electrode, this liquid is constantly withdrawn from the tank, cleaned by filters, and then recycled into the tank.

These spark erosion machines usually have mounted on the upper edge of the tank a temperature control and a liquid level control device. In these tanks, the liquid is usually drained through openings in the upper portion of the tank wall or through a drain pipe extending vertically through the bottom of the tank up to the upper edge level of the tank. These drains have the disadvantage in that the tank must always be filled to its upper edge even though the tank need not be only partially filled with liquid in order to cover the workpiece, as, for example, only one-half filled or less if a flat workpiece is being used. Consequently, considerable time is wasted for filling and emptying the tank when it is necessary to inspect the workpiece or adjust or measure the same.

Attempts have been made to reduce the time for filling and emptying the tank with liquid by providing a drainage opening which can be set to diiferent liquid levels. However, such attempts up to now have incurred further :disadvantages.

For example, drain pipes of various lengths have been used which were inesrted into a drain opening in the bottom of the tank, depending upon the liquid depth desired. This required a supply of an extensive number of drain pipes of different lengths, especially if one tried to provide for numerous liquid levels in small increments. But even with a large supply of different length drain pipes for obtaining small increment changes in liquid level, it is still not possible to precisely adjust the liquid level above the workpiece as required by the spark erosion machine and with a minimum of liquid in the tank.

Another used draining system is composed of a flexible bellows tube having a drain opening head within which is a central grooved rod and a spring-pressed ball in the groove. This system likewise has the disadvantage in that it merely permits an adjustment of the liquid level in small increments. Moreover, the flexible bellows tube was non-metallic and deteriorated with age, which resulted in mechanical damages.

Even though these heretofore used drains are adjustable to vary the liquid level to some degree, they have the above-stated disadvantages and, in addition, do not provide for altering the position of the temperature and liquid level control means with respect to the liquid level in the tank. Even though the temperature and liquid level control means ordinarily mounted on the upper edge of the tank could be re-mounted to the liquid level in the tank, such an independent setting from the position of the drain opening is clumsy and inaccurate.

The object of this invention is to avoid the above disadvantages by producing an adjustable drain for the tank in which the drain opening, together with the temperature and liquid level control means, are mutually simply positionable to any given liquid level in the tank.

In general, these objects are obtained by providing a drain tube having its upper open intake end positionable to any desired liquid level in the tank and locked in that position and to which is connected the temperature and liquid level control means.

In this invention, the drain tube is pivotally mounted adjacent the bottom of the tank and joined to a parallel control lever which is also pivotally mounted in the horizontal plane of the mounting for the drain tube, and with the lever and drain tu'be connected by a link which carries the temperature and liquid level control means. The two axes of the pivotal mountings for the drain tube and control lever are parallel in the same horizontal plane. This forms a parallelogram system so that the connecting link is horizontal at any height in the tank. A handle is joined to the drain tube which is accessible through the top of the tank. The pivotal mountings of the drain tube and control lever adjacent the bottom of the tank extend through the wall of the tank. A knob threaded on the shaft forming the pivotal axis for the control lever is turnable so as to bear against the wall of the tank and lock the lever in any desired position. The pivotal mounting for the drain tube is composed of a drain pipe rotatably journalled through the wall of the tank and to which the drain tube is rigidly connected, preferably at a right angle. The parallelogram system thus established is composed of the drain tube, the control lever, and the link carrying the temperature and liquid level control means, and which system is swingable on the pivotal mountings. This system has the advantage in that the temperature and liquid level control means remain horizontal at any given depth within the tank and are adjacent to the intake opening of the drain tube. Also, practically any given liquid level in the tank can be set.

The means by which the objects of the invention are obtained are described more fully with reference to the accompanying drawings in which:

FIGURE 1 is a cross-sectional view through the spark erosion machine tank of this invention;

FIGURE 2 is an enlarged detailed partial cross-sectional view taken on the line 2-2 of FIGURE 1; and

FIGURE 3 is a similar cross-sectional view taken on the line 33 of FIGURE 1.

As shown in FIGURE 1, the spark erosion machine 1 includes a workpiece table 2 contained in a tank 3 which is adapted to hold liquid at a level above and covering the workpiece. Tank 3 has an opening 4 closable by a door 5 and locked by means of knobs 6.

As shown in detail in FIGURES 2 and 3, the wall 7 of tank 3 has adjacent thereto a drain tube 8 which has its lower end pivotally mounted adjacent the bottom of the tank. This pivotal mounting is composed of a fitting 9 comprising a drain pipe 10 to which the drain tube 8 is connected at right angles by a weld 11. Pipe 10 forming the pivoting axis for the tube 8 is drawn up against the wall of the tank by two nuts 12 threaded on the pipe so that the pipe can be rotated without effort. A continuing drain pipe 13 leading to the oil filters communicates with pipe 10 through a seal 14 and a welded-on coupling 15 fastened to tank 3 by three bolts 16.

At the upper open intake end of a drain tube 8 is welded a stud 17 having a journal 18. A link 19 is journalled to the stud and carries a housing 20 in which there is the temperature and liquid level control means. The other end of link 19 is connected to the upper end of control lever 21 by the pivot point 22. The lower end of control lever 21 is connected to a shaft 23 by a weld 24, which shaft is journalled in a bearing 25 extending through wall 7, this bearing being in the same horizontal plane as the drain pipe 10. Drain tube 8 and control lever 21 are parallel to each other. A seal ring 26 prevents leakage around shaft 23. Knob 27 threaded on the outer end of shaft 23 is turnable so that it can be jammed and locked against wall 7 and thus permits an infinitely variable positioning of the intake end of drain tube 8. Thus this parallelogram system can be swung to any position by means of handle 28 and then looked into place by knob 27. As shown in FIGURE 1, the vertical position of drain tube 8 is shown in full lines, while the half-way and lower positions of the parallelogram system are represented by the dotted lines 29 and 30, respectively. As shown, the temperature and liquid level control means in housing 20 remains horizontal in any position and always adjacent the upper intake end of drain tube 8. The drain 31 in the bottom of the tank is used for quickly draining the tank and is only incidentally shown.

Having now described the means by which the objects of the invention are obtained,

We claim:

1. An adjustable drain for the workpiece tank of a spark erosion machine comprising a drain tube, first pivot means positioned adjacent the bottom of said tank for locating the upper intake end of said tube at any given height above the bottom of the tank, a control lever extending parallel to said drain tube, a link between said tube and said lever, temperature and liquid level control means mounted on said link, second pivot means in the horizontal plane of said first pivot means for joining said drain tube and control lever in a swingable parallelogram system, a handle secured to said intake end of said tube, and lock means for holding said tube at the given height.

2. An adjustable drain as in claim 1, said first pivot means comprising a drain pipe rotatably mounted in the wall of said tank and joined to said tube.

3. An adjustable drain as in claim 2, said second pivot means comprising a shaft journalled in the Wall of said tank and carrying said locking means.

References Cited by the Examiner UNITED STATES PATENTS 1/1919 Upham l37579 12/1962 De Moine 219-69 

1. AN ADJUSTABLE DRAIN FOR THE WORKPIECE TANK OF A SPARK EROSION MACHINE COMPRISING A DRAIN TUBE, FIRST PIVOT MEANS POSITIONED ADJACENT THE BOTTOM OF SAID TANK FOR LOCATING THE UPPER INTAKE END OF SAID TUBE AT ANY GIVEN HEIGHT ABOVE THE BOTTOM OF THE TANK, A CONTROL LEVER EXTENDING PARALLEL TO SAID DRAIN TUBE, A LINK BETWEEN SAID TUBE AND SAID LEVER, TEMPERATURE AND LIQUID LEVEL CONTROL MEANS MOUNTED ON SAID LINK, SECOND PIVOT MEANS IN THE HORIZONTAL PLANE OF SAID FIRST PIVOT MEAN FOR JOINING SAID DRAIN TUBE AND CON- 